PROJECT ABSTRACT As the population ages, the prevalence of Alzheimer?s disease and other dementias is increasing as is the need for caregivers to assist persons with dementia to complete activities of daily living. Families provide care at home for most persons with dementia. However the stress of caregiving leads to negative caregiver outcomes including depression and increased morbidity and mortality. One of the greatest challenges for caregivers relates to loss of communication abilities in the person with dementia that progress along with cognitive decline. Communication breakdown effects all aspects of providing care as well as relating to a person with dementia. Current communication knowledge and dementia caregiver training is primarily anecdotal and focused on institutional (formal) caregivers. Evidence-based knowledge is needed to inform effective interventions for family caregivers to support successful communication that facilitates care and maintains interpersonal relationships. The goal of this research is to identify evidence-based caregiver communication behaviors and strategies that prevent and successfully resolve communication breakdown. We will complete a secondary analysis of over 200 video recordings captured at home by fifty-one family caregivers. These unscripted, spontaneous care episodes were recorded in our recently completed Supporting Family Caregivers with Technology for Dementia Home Care (FamTechCare) telehealth trial (R01NR014737). We will adapt validated measures of caregiver communication behaviors (based on the Verbal and Nonverbal Interaction Scale, Caregiver version) and indicators of communication breakdown and successful versus unsuccessful repair (based on the Trouble Source Repair Model) to frame-by-frame behavioral coding analyses. We will use sequential and linear regression analyses to identify what communication strategies are associated with successful communication (prevention and successful resolution of communication breakdown) within and between dyads. We will evaluate covariate factors to identify strategies with differential effects based on dyad characteristics such as relationship and type and severity of dementia diagnosis. These findings will be used to develop caregiver communication interventions. Because communication is critical to all aspects of dementia care, increasing caregiver communication skills can facilitate care, reduce the stress and burden of caregiving, and support interpersonal relationships so families can continue dementia home care. This research targets the National Plan to Address Alzheimer?s Disease goal to expand support for people with Alzheimer?s disease and related dementias and their families.